This project will evaluate the feasibility of argon and CO2 lasers for performing ablative surgery of the middle ear and semicurcular canals of experimental monkey subjects. In addition to delineating safe and appropriate output parameters (burst duration and power levels) for vaporizing or perforating hard and soft otic tissues, auditory and vestibular function will be measured electrophysiologically and behaviorally in order to determine if laser microsurgery is accompanied by harmful and sensorineural side effects. After completing all functional measurements postoperatively, the animals will be sacrificed and temporal bone sections processed for evaluation of inner ear morphology. BIBLIOGRAPHIC REFERENCE: Wilpizeski, Chester R. Otological applications of lasers. Chapter 4 in M. Wolbarsht, ed., Laser applications in medicine and biology, vol. 3, Plenum Press, 1977.